The present invention relates to a graphic drawing method and graphic drawing device for drawing a graphic in a specified area, and more particularly to a graphic drawing method and graphic drawing device which can draw a high-definition and high-resolution graphic with a small storage capacity when clipping any optional shape.
Previously known techniques for clipping any optional shape include a working area technique and a square clipping technique.
In the working area technique, in order to clip an optional shape, a clip frame memory having the same size as that of a frame memory is provided as a working area and a storage area, and a clipped graphic is once drawn on the clip frame memory; in actually drawing a graphic, the filling-over thereof is made with reference to the clipped graphic stored in the clip frame memory. Incidentally, as disclosed in JP-A-59-85573, a graphic can be drawn by clipping for each scanning line using a memory corresponding to one scanning line. On the other hand, in the square clipping technique, in order to clip any optional shape at a high speed, the clipped area is divided into minute square regions; in actually drawing a graphic, clipping for the plural minute regions thus formed is carried out to approximate the optional shape.
The prior art techniques mentioned above are disadvantages in that the working area technique provides inefficient use of memory since the clipping memory having a large size is required for an output device with a high resolution such as a printer. On the other hand, the square clipping technique has no problem of efficiently using memory, but it cannot be used when high drawing quality is required in e.g. a printer owing to its approximation manner.